


The 'What's happening to my body?' Book for Omegas, and Other Trials of Coming of Age

by byesweetheart (ConstantComment)



Category: Haikyuu!!
Genre: Alpha Nishinoya Yuu, Alpha/Beta/Omega Dynamics, Basically, Best Friends, Birth Control, Embarrassing Parent Stories, First Time, Friends to Lovers, Haircuts, Hormones, Knotting, M/M, Mating Cycles/In Heat, Mild D/s if you squint?, Noya Is Good Alpha, Omega Tanaka Ryuunosuke, Omega Verse, PMS stuff basically!, Rimming, Secret Crush, Soft Boys, Stereotypes, Those are tags already and that's awesome, Trope Subversion, and the body fluids thereof, can be shitty
Language: English
Status: Completed
Published: 2020-08-31
Updated: 2020-08-31
Packaged: 2021-03-06 15:28:05
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 3,254
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/26221147
Author URL: https://archiveofourown.org/users/ConstantComment/pseuds/byesweetheart
Summary: Heat suppressants have never worked well for Tanaka. It's great that Noya is such a good friend.
Relationships: Nishinoya Yuu/Tanaka Ryuunosuke
Comments: 15
Kudos: 216
Collections: "In Their Prime" Sportsani Exchange





	The 'What's happening to my body?' Book for Omegas, and Other Trials of Coming of Age

**Author's Note:**

  * For [Mother_of_Eevees](https://archiveofourown.org/users/Mother_of_Eevees/gifts).



> Alibee!!! I glommed onto TanaNoya when I saw it on your prompt, and kind of ran with it! I hope you like this little experimental Omega Tanaka. :') I really like trying ABO stuff and exploring character traits in that context, so I hope it's fun and cute, and hopefully not too spicy/messy? (By which I mean, just the right amount of spicy/messy.)
> 
> Other Notes:  
> \- Self-edited, so literally all mistakes are mine forever and always  
> \- I would apologize for the localizations that are in this, but 1) the amount of "bros" that are in this seem aligned with the manga translations, and also 2) it's funny so I'm not really sorry.  
> \- I did not mark underage since Tanaka's 18th is within literal days of doing the do, and Noya's canonically older. If that's a problem, please X out!  
> \- Other possibly squicky things are tagged  
> \- Note for everyone else, first time writing in a while and I'm rusty, so be nice to me! ;)

The metallic rumble of the clippers buzzes against Tanaka's head in slow strokes, lulling him a little like a rocking chair as familiar fingers tilt his head this way and that.

"She really won't let you just... stop taking the suppressants? That's bogus, you're of age next month!"

Noya's voice is equal parts annoyed and absent while he curves the clippers around the shell of Tanaka's ear, and Tanaka can't help but look into the bathroom mirror at his best friend's reflection, watch him finish off the last hairs at Tanaka's nape. _Not_ watch his sharp eyebrows knit together, or watch him lick at his canines in that weird habit he has when concentrating. He does it before diving for a ball on the court, too.

Thankfully, Noya's not as sweat-shiny as he is during practice — that was hours ago, before homework and a quick trip to the store for melonpan and bleach for Noya's hair. Now, he's got a towel around his shoulders and his hair is drying slowly after a quick dye job over Tanaka's sink. Water droplets slip down his neck into the terrycloth, and his hair looks soft without the gel he uses to slick it skyward. Tanaka is very glad he's not in the middle of his heat now, when he'd probably do something stupid and horrible like _pet_ Noya — suppressants or not.

"I haven't even bothered asking," Tanaka whines, letting his head fall back in despair before Noya corrects him with a flick to the back of his skull. "The last time I asked she gave me a book called _The 'What's happening to my body?' Book for Omegas_ , and told me all about how I wasn't ready for heats yet, but when I was old enough and _found someone special_ and _intense feelings_ and _trust and intimacy_ — "

Noya's brows rise and he grins, even as his cheeks pink up, and Tanaka is not-so-secretly glad he doesn't make eye contact in the mirror.

" — and a whole bunch of stuff I can't even _think_ about and I _died_. And _then _she said I was lucky that suppressants were so advanced these days!"__

Noya brushes his hand over Tanaka's head, and they both chuckle a little when he hams it up and sighs dramatically at the fuzzy prickle of Tanaka's renewed buzzcut. "Lucky you get mood swings and cramps and stuff?"

"Better than migraines so bad I wanna puke, I guess," Tanaka says, flipping his hands into the air, before letting them fall to either side of his seat on the side of the tub.

"I _guess,"_ Noya agrees reluctantly, knowing how mystified they both were when Tanaka presented as an Omega, despite his size and temperament pointing in the opposite direction. Back then, Noya had to start bringing him his classwork some days, because Tanaka couldn't get out of bed due to the regimen they'd had him on. "Sucks, man. I mean, I know Alphas get some symptoms, but nothing like that. And the talk with my parents was just, 'Dont. Get. Anyone. Pregnant. Or. So. Help. Me — '" he waves the clippers around like a baton, before unplugging, wrapping the cord up and shoving it into the cabinet under the sink.

"Yeah, rub it in," Tanaka jokes.

Noya grins and does just that — returns to rub Tanaka's head roughly, before drumming a beat into his shoulders, all finished with his work.

Tanaka shakes his head a bit. He smoothes a hand over his skull with a small grin, and stands. Which is a stupid move while Noya has his hands on his shoulders.

They look at each other for too long.

Noya's still a shortie, but once he presented as an Alpha something about him changed — or maybe it just solidified — something that feels an awful lot like... well, Tanaka can't call it anything but _capable?_ It's a weird feeling to put into any words, which is why Tanaka will never tell him.

Noya's got a big enough ego anyway, now he's of age. His head might burst if Tanaka said something like: 'Hey man, your confidence sometimes messes with my heat suppressants, and I can't tell if it's worse (better?) than the mood swings.'

Yeah, Tanaka certainly can't tell him any of that.

Smacking Tanaka's cheek and popping any lingering thought bubbles out of the air between them, Noya drops his hands to his own shoulders and slips the towel over his head for one last tousle. When his face reemerges, his cheeks are even more pink than before.

"Hey... Ryu, you know — you can talk to me if you're feeling down." He turns and underhand tosses the towel into the hamper in the corner, like he's lived in the Tanaka household all his life. In some ways, he has. "Just because I'm an Alpha doesn't mean I'm not your best bro when you're at your most... Omega-y."

Tanaka nods, hand creeping up to his scalp out of habit.

"You talk to me. Call me. Whenever. Or, yeah, whatever. If you gotta be on those stupid pills then... I'll help if I can."

Deep brown eyes stare up at him, and it's times like this that Tanaka hates being an Omega, because the inside of his chest goes all tight and soft at once, and his stomach heats like a flashbang, like the quick smack of a volleyball against shining gym floorboards.

He's struck dumb.

"Yeah, uh," Tanaka says, nods, and wonders if he's closer to his heat than he realized. "Thanks, Noya."

Noya smiles and tilts his head in that cocky way he has, and turns from the room. "Wanna play Smash before your mom gets home?" he calls down the hall.

Tanaka blinks. "You mean, obliterate you in Smash before my mom gets home?"

Noya's incredulous laugh bounces through the house.

/\/\/\/\/\/\/\/\/\/\/\/\/\/\/

"'lo?"

"Noya," Tanaka says into his phone, then winces at the way he sounds. Breathy. Pathetic? Both, probably.

"Tanaka, hey. It's — wow, you're up late," Noya says groggily, voice a little rough, but his voice gets clearer as he shifts around on his futon.

Tanaka glances at the glowing clock across the room again: 1:03 AM. He wipes at his cheeks, because there's no way he can call his best bro in tears. "Sorry, man, I — "

"You okay?"

"Yeah, I... uh... No, I guess not," Tanaka says, voice petering out. Why did he dial? Noya was just being nice when he'd said to call. It's not like it was an open invitation to spill his guts whenever!

Noya hums quietly. "I wondered if you were in heat — " he says, before cutting off abruptly. "You just seemed a little off in practice. What's up?"

"You said, that time. Couple weeks ago," Tanaka starts, swallowing as he sinks back into his pillows again and unplugs his phone from his charger. "You said I could talk to you if..."

"Of course. Tell me, Ryu."

Tanaka closes his eyes at his name, quiet, in his ear. "This heat is real bad," he eventually admits, letting his voice grow small. "I feel like a steaming pile of crap."

Noya's huff crackles through the receiver, and Tanaka imagines he's smiling a little. Maybe he's got his eyes still closed, listening on the edge of sleep. "I'm sorry bud, you hurting or... like, uh, cramps and stuff or, you know, feelings and stuff?"

Tanaka groans a little, "Ugh, both."

"You get your heating pad?"

"Ugh," Tanaka affirms. "I'm gonna sweat through my sheets."

"Oof," Noya says, a soft croon of commiseration.

"And I already feel gross and... and unloveable. And stuff."

Noya is quiet for a long moment. But then, he's back, voice clear as crystal. "Forget the sweating, that's for future Tanaka to worry about," Noya says first, which makes Tanaka chuckle a little, pain in his belly and hips dimming for a brief, glorious moment. And then, "Let's get you more comfortable, Ryuu — why don't you pull all your pillows into a nest? I know it's cliché, but — "

Tanaka can't help but smile. "Yeah, okay."

Noya talks a little about a dream he'd been having a while Tanaka struggles with his bedding, clumsily fluffing up the pillows and pulling them this way and that until he's surrounded by them, heating pad tucked behind his back, almost like — almost like someone's curled around him, warm and close.

"Good?"

"Better," Tanaka says, a sigh escaping before he can tamp it down.

"You sound better. All cuddled up." There's a warmth in his voice that sticks, drags down Tanaka's spine and deep into his stomach and curls there with a strange, humid heat, and Tanaka blinks, another sigh slowly whistling between his teeth.

"I'm sorry you're feeling like crap," Noya continues, soothing but still awake, alert, like he's taken over so Tanaka doesn't have to hold it together anymore. "You wanna tell me what's got you down?"

Tanaka swallows. "Oh, you know. Just, thinking about how I'm going to be on shitty suppressants _forever,"_ he grumbles. "Gonna be stuck with dry heats and cramps and pills for eternity and I'm gonna die alone because I'm a terrible Omega."

"It's not forever, Ryu, you know that," Noya says, certain.

"But no one likes me," he insists, and sniffles, because he's pathetic. "No one's gonna wanna be my heat partner because no one wants a big, gawky, ugly Omega, even when I'm of age."

At that Noya lets out a disbelieving laugh.

"Don't laugh at me!" Tanaka says, stung.

"Can't help it! You're _not_ gawky, and you're _not ugly,_ holy shit. You're tall and athletic and funny and — " Noya groans a little. "But so what? What's that got to do with being a good Omega?"

"You know what I mean!"

"What about me, then? I'm not a stereotypical _asshole Alpha_ with huge muscles or whatever," Noya says, terse, and Tanaka sucks in a breath. "Does that make me the worst?"

 _"No!"_ Tanaka says. "'Course not, bro — _Noya_ — "

"What does that make me then?"

"You'd be the best Alpha, you'd be so good," Tanaka says without thinking, breathless and squirming.

Noya is silent on the other end.

"Yeah?" Noya says, eventually, whatever sharp confidence he carried now a little rounder, softer, as it moves from his lips to Tanaka's ear.

"Don't make me repeat it," Tanaka says, low.

They breathe together for a moment, until Tanaka takes stock of his body and realizes that... the suppressants don't seem to be working. Maybe he was a little lax taking his pills on time this month, because he's hot and soft all over except for his dick, which is nudging insistently into one of his pillows, while his thighs slide slickly together.

He's wet.

"Shit," Tanaka sighs. He wants to touch himself but Noya's on the line, and if he touches himself with Noya there, then he's even more pathetic than he thought.

"Ryu, you okay?"

Tanaka swallows again, closes his eyes and clutches at his pillows. "'M fine."

"Ryu."

Tanaka squeezes his eyes shut as his body curls against the sound of his best friend's voice.

"Ryu, your next heat — what if someone did want to be your heat partner?" He clears his throat. "Your Alpha?"

Tanaka shifts and winces at the wave of heat that rolls through him. "What about my meds?

"If you didn't take your meds?"

The realization blooms slowly, and he finds himself grinning and hiccoughing as his hormones ricochet inside his ribcage. He wipes at his eyes with his wrist and shudders as Noya grumbles about being left hanging.

"You wanna be my heat partner?" he asks, water-logged.

"Yeah, bro. Since forever," Noya says, and if Tanaka weren't so nice he'd call him out for sounding so bashful. He'll tease him later. "Wait, are you crying?"

 _"Nooo,"_ Tanaka insists, but snorts horribly when Noya starts laughing.

"Aw, Ryu, is it that bad?"

Tanaka's laughter punches out of him, because he knows Noya's ribbing him now.

"Worst Omega and Worst Alpha sounds like a disaster," Tanaka says, stretching out in his nest and letting himself bask in the heat now, even though there's no recovering from the slick between his legs. He'll have to do something about it as soon as Noya hangs up, and catches himself thinking about Noya's fingers in his hair, how they'd feel nudging him into position —

"They cancel each other out," Noya says, deadpan, and Tanaka squawks, because he's gotta be delirious now. He slaps a hand over his mouth as Noya shushes him, laughing, until they both calm down.

When Tanaka wakes in the morning, one hand holding his phone and other hand still crooked uncomfortably to reach inside himself, he grins, laughs into his pillow, and thinks about flushing his pills down the toilet.

/\/\/\/\/\/\/\/\/\/\/\/\/\/\/

They don't quite make it to Tanaka's birthday.

Turns out that taking suppressants doesn't just suppress heat, Tanaka finds, because within a week he's had nearly a million terrible boner mishaps at school and after.

 _After_ being when he and Noya catch a movie and end up making out until they're both incoherent, or when they bike home and stop in the big park in the cool air of early March and end up wrestling... if you can call it that... under the cover of a couple old willows, or when they sneak into the equipment closet and Tanaka gives into the urge to go down to his knees at Noya's feet.

Thankfully, it's only in private that Tanaka soaks through his underwear.

Plus, he's got a change of clothes at the gym. And it's all worth it when he's able to get Noya whimpering and almost knotting even before he's pulled him out of his volleyball shorts and into his mouth.

Noya is sweet, but not malleable, his whipcord muscles clenching as he scratches his blunt fingernails over Tanaka's head and presses his jumping cock into Tanaka's mouth through his shorts.

Tongue swiping over his canines when Tanaka finally sucks the head between his lips, Noya grunts soft and sure, "Wanna be my good Omega, huh?"

And Tanaka's eyes roll back in his head.

Nothing beats the heat, as they say, but some things can trigger it.

They go to the Nishinoya's since Tanaka's sister is home, and Noya wastes no time.

He shoves Tanaka gently into the back of the couch so he can angle into a kiss, so Tanaka can feel a little cradled when two square hands come up and press gently into his jaw, opening his mouth so Noya can do as he likes.

"Noya," Tanaka rasps when those sharp little teeth graze over his neck, because he's shaking, and if they stay here any longer he's worried about soaking into the couch. "I gotta — _please..._ "

"Go shower, Ryu, get all warm and soft, and I'll get us ready in my room."

Tanaka didn't realize how easy it would be to do as Noya asks. He's not sure if it's an Omega-thing or a them-thing, but either way it's _awesome,_ and he's shivering and hard and slick the moment he steps under the spray and then out. He practically trips over himself to get to Noya's room.

When he gets there, there's a big nest of pillows where Noya's futon usually rests, with blankets and sheets whirled into a blissful-looking cloud while beside it condoms and lube are arranged neatly (in case he's _not somehow slick enough_ ).

Noya is stripping out of his shirt, boxers tented, when Tanaka stumbles in. Within seconds, he's got his hands around Noya's ribs, nuzzling into his nape, and Noya laughs, grabs his hand as he pulls off his shirt with the other. They practically frogmarch to the nest, but the playfulness softens into something else when Noya turns and presses Tanaka to the floor.

His knees land on the soft blankets, and he melts further into the bedding as Noya drops his boxers. Noya's not huge, but he's not _not_ huge, bigger even than he was when he was standing over Tanaka less than an hour ago after practice.

"Alpha," Tanaka groans, knees falling apart to each side. It just scrapes out of him as Noya fists his cock and strokes a couple times, dripping from the slit in a way that makes both Tanaka's mouth water, and his stomach clench. Tanaka blinks at his own thighs, which are shiny, and between them, pink with heat.

Noya nearly falls to his knees, and when he stretches out between Tanaka's legs, he slowly slides his belly and his cock against Tanaka until their scents swirl together. "You smell amazing," Noya rasps, looking flushed and hazy with want. "So good." And then he kisses him again, tongue and teeth indulgent and consuming.

Tanaka's soaking, moaning and grinding into him, seeking out something to fill him when Noya starts to kiss down his neck, his pecs and his heaving belly, before he laps at Tanaka's cock, making him twitch and drip on a long moan.

"Just you wait," Noya murmurs against his shaft, and then he moves further down, groans in surprise when he tastes Tanaka, right against his hole.

"Holy shit," Tanaka says, voice thinning to a whine, _"Noya."_

"Ryu," Noya groans and laps at him until Tanaka can't bear anything but holding onto Noya's hair as he shakes, incoherent with the heat pulsing out of him.

"'M ready, c'mon Noya. Want you to knot me," Tanaka insists, ploughing canals through Noya's hair with his long fingers. "Alpha, please."

Noya swears and bites into Tanaka's thigh, sharp, before he sits up and fumbles for a condom. His cheeks and mouth are shiny with slick, and Tanaka blinks at him, then up at the ceiling, when he can't catch his breath. When he can't believe what he's seeing.

"Tanaka — Ryu, come back." Noya's soft command pulls Tanaka back, and they watch each other closely as he lines his red cock up and slides into him, tight and easy.

Overwhelmed and full, Tanaka lifts his hands back to Noya's hair, petting him as Noya's face transforms with pleasure, eyes fluttering.

Noya swears again, before muttering, "I'm gonna knot so quick."

"Fuck, do that," Tanaka agrees, and his body moves on its own when Noya slides all the way home.

"Need to fill you up," Noya replies, "Knot you good," like he has no control over his mouth anymore, and as much as Tanaka liked Noya in command, he really likes Noya without any sense left.

"Good," Tanaka laughs as their heads fall back, and they rut against each other, hands scrabbling over bellies and chests. If Tanaka was slick before, he's soaking now, and the sound of them, the sound of Noya's growing knot catching against his hole before slipping back inside, makes him shiver and clench around his best friend.

"Ungh, I'm — Ryu, sorry I'm going to come like — "

"Right now, Noya, please," Tanaka finishes for him, and Noya falls forward, hips snapping again and again until Tanaka reaches up and licks into Noya's mouth, tastes his own slick, while his body clenches around him, trying its best to hold him inside.

Noya whimpers, makes the most tortured, blissful sound, and Tanaka feels the moment he knots, hips twisting and grinding and shuddering.

Tanaka holds tight as he splashes his own belly with come.

/\/\/\/\/\/\/\/\/\/\/\/\/\/\/

"Remember that one time you said you were a terrible Omega?" Noya says later, soft-bruised lips tickling Tanaka's jaw.

"Can't recall," Tanaka says, and Noya laughs and grinds gently inside him, rubbing a hand over Tanaka's scalp once more.

**Author's Note:**

> Comments & kudos are love // @byesweetheart_ on twitter


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